Japanese robots long gone before Fukushima accident
One of the remote-controlled robots built for a nuclear power plant accident a decade ago today gathers dust at the Sendai Science Museum. (Ryuichi Kanari)
Five years before the Great East Japan Earthquake and tsunami triggered the crisis at the Fukushima No. 1 nuclear power plant, Japan's six robots that could venture into a radiation-filled reactor building were consigned to the scrap heap.
The reasons ranged from the uneasiness they caused nuclear plant employees, to the belief that a nuclear power accident could never occur in technologically advanced Japan.
So, in a blow to the world leader in robotics, since April 17, the remote-controlled robots going where no man dare go in the crippled Fukushima plant were made in the United States.
"There was a consensus that it was necessary to prepare for emergency situations," said Takahisa Mano, a member of the research division of the Manufacturing Science and Technology Center, a public organization that promoted the development of Japanese robots after the JCO Criticality Accident in 1999 that killed two workers. "But electric power companies had a strong belief that those robots are not necessary because accidents do not occur at nuclear power plants."
Satoshi Tadokoro, professor of robotics at Tohoku University, said the robots were built in 2001 with existing technology, but would have improved greatly over the years if Japan had followed through with the project.
"If the robots were put into practice, their abilities would have been improved in the subsequent 10 years," Tadokoro said. "As a result, in the current nuclear crisis (at the Fukushima plant), they would have contributed to decreasing the burden on workers and the amounts of radiation they were exposed to."
The six remote-controlled robots for nuclear power plant emergencies were developed under a government budget of 3 billion yen ($38 million) to deal with possible accidents at nuclear power plants. Their development resulted from the so-called JCO Criticality Accident in Tokai, Ibaraki Prefecture, in which an uranium solution accidentally reached criticality in JCO's facility, causing a nuclear fission chain reaction and killing two workers exposed to the radiation.
Four companies, including Hitachi Ltd., Mitsubishi Heavy Industries Ltd. and Toshiba Corp., developed and manufactured the six robots in 2001 following the accident. The robots were built to endure deadly radiation levels of 10 sieverts per hour.
Much of the government budget was used for testing to confirm the robots' durability under high radiation levels. Robotics experts gave high marks to the completed robots, saying that they sufficiently met international standards.
According to engineers involved in their development, however, when the manufacturers suggested to electric power companies that the robots be placed at their nuclear power plants, employees at the utilities showed much uneasiness and started asking questions.
One asked, "Will accidents take place at nuclear power plants? What kinds of accidents? When?"
A task force consisting of five members, including executives of Tokyo Electric Power Co. (TEPCO), Kansai Electric Power Co. and a government-affiliated organization on nuclear power development, considered whether to use the robots.
In December 2002, however, the group concluded that there would be few cases in which the robots would be utilized.
While the robots could be used to check and monitor sites while enduring high levels of radiation compared to humans, they would walk much slower and their range would be limited, the group said.
They also thought humans would still be able to work in a disaster-hit nuclear plant.
Consequently, the robots became expendable in March 2006 when their storage periods ran out. As a result, four of the six robots were given to Tohoku University. Of the four, one is now exhibited at the Sendai Science Museum.
The robots had been made with state-of-the-art technology of the time, including the ability to take water samples in reactor buildings. However, a curator at the museum said, "We don't know whether it can even be operated now."
Another robot was donated to a citizens' organization. The group dismantled it as a learning tool for children and later disposed of it.
Meanwhile, the United States and some European countries were placing a priority on utilizing robots in time of nuclear power-related disasters.
After the JCO accident in 1999, some researchers took part in an overseas research team that gathered ideas for the development of Japanese robots.
They learned that Germany had a system for dispatching robots within 12 hours after nuclear accidents occurred. Operators of the robots were receiving training five times a year, with each session lasting two weeks. France also had a similar system.
An executive of an electric power company, who was a member of the task force that concluded in 2002 that the robots were unnecessary, said, "We had a mind-set from many years ago that humans could go into the accident sites in emergency situations. We did not imagine that serious accidents could take place."
As for the 1986 Chernobyl accident that occurred in what was then the Soviet Union, the executive said, "We did not think about it as our own. We were not humble."
(This article was written by Seiji Iwata and Ryuichi Kanari.)
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